Tutorials Home Page  |  Colors & Density  |  Complete Example  |  Single Color Design

More Detailed Colors and Density Tutorial

This is an additional tutorial for multicolor Sfumato Stitch. Its meaning is to provide deeper insight into how the program converts image into stitches. This knowledge should help users to create better designs with less effort.

The Colors and Density subjects are discussed in further text.

Colors

What is the meaning of Color Map ?
The easiest way of design creation is to just hit the Auto button and let the program chose the thread colors automatically. This can be used as a first step, but usually some further adjustment of parameters is necessarry to produce really good designs. For example, if there are similar colors on shirt and face (like on above picture), program may assign face colors to shirt because it doesn't know where the face ends and shirt begins. Therefore, Color Map is accessible to user for manual editing to adjust colors layout. Of course, if edited Color Map is used (loaded), program can no longer allow user to change some parameters, because edited Color Map would be replaced by new automatically generated Color Map. Therefore, some controls are locked after loading of edited Color Map.

Why is the Color Map displayed in untrue colors when loaded into Painter for editing ?
Imagine the situation when you are working on design with lot of similar color like yellow, orange, light red etc. If you would edit the Color Map of such design in real colors, some solitary dots and thin lines will be hardly visible. Moreover, if you change the thread colors, Sfumato would be not able to read this edited Color Map because it would not recognize its colors. Therefore, Color Map is saved in untrue colors that are always the same regardless of thread colors used in design. Thus, the details are more visible when editing the Map and Sfumato can read edited Color Map even if thread colors are changed.

What are Color Scales ?
Sfumato reduces millions of colors in image to just several chosen Palette Colors. To achieve subtle graduation of brightness, Sfumato divides each palette color into 4 different shades: Darkest Thread Color (usually black), Dark Thread Shade, Light Thread Shade and Lightest Thread Color (usually white). When creating multicolor design, Darkest and Lightest colors are common for all color scales. For example design in red and yellow scales would be sewn with following threads: black, white, dark red, light red, dark yellow, light yellow. Any of these colors can be omitted by proper adjustment of particular Threshold value.  

The process of colors reduction is following:
Millions of image colors --> Palette Colors chosen automatically or by user --> Thread Shades.

The processing of image by Sfumato can be devided into following main steps:

1. Editing of image and elimination of backround in Painter.
2. Hitting of Auto button to achieve preliminary version of design.
3. Adjustment of design parameters, colors and their number.  
4. If preview of design is still not satisfactory, the editing (retouch) of Color Map.
5. Calculation of design based on original or edited Color Map.  

How should you choose the Palette Colors ?

When you hit Auto button, program choses Palette Colors and their number automatically. However, automatical choise is often not optimal. To choose Palette Colors manually make the following:

1. Decide what number of color do you need (two shades for face, one shade for shirt ... etc.). Enable corresponding number of scales. If you need just one shade from scale, adjust the threshold accordingly.

2. Click on Palette Color box to access the color editing window. On the right side is color square with all posible image colors (deprived of brightness). This color square is Color Palette from which you can choose several Palette Colors. On the left side, you will find the Colors Histogram that shows how often colors from palette appear in the image. The more frequent is the use of color in the image, the brighter is the corresponding spot in the Histogram square. Black color in Histogram means that color is not used in image.

3. The strategies for choice of just few Palette Colors for a good approximation of millions of image colors may be different and none of them is universal. You should combine below methods and find what is best for particular image.
a) You can choose the colors that are mostly used in image. In such case, place the Palette colors into brightest spots of Histogram. However, imagine picture with sky where are many shades of blue and small yellow moon. Using this approach, you will choose several blue Palette Colors but no yellow. The moon will be blue after colors reduction.
b) You can choose colors that are sufficiently different one from other. This approach does not take into account amount of color in the image. You may have a lot of unnecessary thread colors in your design then and some colors will be used only for a few stitches.
For best result you should combine approaches a) and b), i.e. place Palette Colors into centers of brightest clouds (aggregations) that are sufficiently distant one from other at the same time. The number of bright clouds also shows you how many Palette Colors should be used for your image to achieve design with similar look as image.
You may need to emphasize colors sometimes, to get more distinctive aggregations in the Histogram. Adjust Saturation of image colors in this case. You can also select some part of image (moon for example) and change the Color Balance so that it will be more yellow, or green ... Doing this, you do also change the aggregations in the Histogram.

The color layout of design is derived from color component of image. The actual density of thread that forms the three dimensional look of design is calculated from brightness component of image.

User can bias the thread density with use of following (all three ways can be combined):

1. Adjustment of the brightness and contrast or equalization of image or just its selection. 

These controls are mostly used to improve scanned image to look good on the screen. Scanned images are often too dark, bright or have low contrast. Use these controls for preliminary adjustment of image. They can be used on whole image or selections.

For further enhancement use Equalize function. It is very important function that should be used on almost all images.

For final adjustment of stitches density use Density Curve and Additional Density controls. These controls do not affect the image. They influence the way of conversion of image into design.

Usually, the Equalize function significantly impoves the look of finished design. Use it separately for hair, shirt, face or other parts of design to achieve best results. Equalized face or shirt may look rather dark on image on screen, but design will look more three-dimensional with emhasized shadows and highlights. Be not disturbed with how the image looks on the screen, do all adjustements so that preview of design looks good.

Density Curve determines which shades will be sewn with larger or with lower density. Imagine the diagonal going from left bottom corner to right top corner. If point on curve is under diagonal, the image areas with corresponding brightness (horizontal axis) will be sewn with greater density than normal. If point on curve is above diagonal, the density will be lighter than normal. Normal density is given by diagonal, i.e. large density for dark areas and low density for bright areas.
Density is adjusted regardless of colors. Only the brigthness is taken into account in this case.
If you want to adjust density of some color area, use Additional Density controls (see below) instead or select color range of image and adjust its brightness, contrast, gamma or equalize it.